This Note will analyze the Tax Court decision in O'Donnabhain v. Commissioner [134 T.C. 34 (2010)], and raise questions about its implications. The issue before the court was in essence a medical question regarding the scope of the medical deduction, and the court followed the traditional course in transgender jurisprudence, relying on medical evidence and the diagnosis of a disease to permit O’Donnabhain’s deduction for her sex reassignment treatment. However, there is much debate within the transgender community about reliance on the medical model. Part I will provide a brief history of O’Donnabhain, her condition, the treatment she sought, and her struggle to defend her rights. Part II will explore in further detail the definitions and case law that formed the basis of the Tax Court’s decision. To conclude, Part III will explore how the Tax Court’s choices in statutory interpretation impact the transgender community and broader advocacy efforts. It will also raise the possibility that a future taxpayer could rely on the second prong of the definition of medical care for a deduction, thus expanding the legal recognition of transgender rights.